DEVELOPMENT OF PLANTS 



203 



some of its characteristics will reappear in Bryophyta. The 

 gametes themselves, however, show the same range of vari- 

 ations as previously noted. In the simpler types of this genus 

 they are quite alike and on the same p'ane of differentiation as 



Fig. 119. Reproduction of Ectocarpus: A, branch bearing several spo- 

 rangia, sp; g, zoospore enlarged. B, branch bearing gametangia, gm. C, the 

 upper motionless gamete (female) surrounded by several still motile gametes 

 (males). D, fusion of the gametes, below the resulting gametospore. 



in Ulothrix, since they sometimes develop as zoospores, directly 

 forming the plant, or they may behave as gametes and fuse to 



